jmh 0.2 reporting issue

[Ruslan Cheremin]

I've just updated to jmh 0.2 from maven central, and noticed many changes
in default benchmark reporting. And there is an issue in "totals" section:
Threads count listed for benchmark inside group are equal to thread count
for overall group. E.g

group                            avgt   4         5   15      263.609
  5.493    ns/op

group:readingDrainer     avgt   4         5   15      209.106        9.899
  ns/op

group:writeFormatted     avgt   4         5   15      288.748       13.236
  ns/op

As you can see, Threads=4 for all lines, while actually it is 1 for
readingDrainer and 3 for writeFormatted. In detailed part of report correct
value of threads are shown, but here it is confusing.

//Ruslan